EVALUATION AND COMPARISON OF METHODS OF FILTERING
NAVAL AVIONICS FACILITY INDIANAPOLIS IN
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The effectiveness of various electrical filters in simultaneous smoothing and differentiating azimuth-angle data was analyzed to determine the optimum method of eliminating noise, Nt, superimposed on the signal, At. Two types of signals were used one was associated with a target on a straight-line path at an angle beta from the ownership course, and the other was associated with the target on a pure pursuit course parabolic path relative to the ownship. The noise function was assumed to have a typical form of the autocorrelation function Rt sigma squared eta sub minus atl, where sigma squared R theta gives the mean square value of the noise amplitude Nt. Evaluation criteria based on the resulting signal distortion and the value of Nt in the output of the filter were selected and brief derivation is included of the Zadeh-Ragazzini Z-R theoretical expressions for filtering J. Appl. Phys. 21 7645-655, 1950 which are based upon the assumption that the signal is representable as a polynomial Pt of degree not higher than a specified number n. The comparative evaluation of various RC filters on the basis of the Z-R theory and the criteria indicated an optimum filter network transfer function which resulted in a mean square noise output less than 25 sq ydsecsec for a 37-ft-long attacking plane. An experimental approach was suggested for future investigations.
- Active and Passive Radar Detection and Equipment